Plants belonging to Camellia L. are very popular in China, Japan, India and many other South-East Asian countries. Among of them, plants from three species C. sinensis, C. oleifera and C. japonica, are of significant economic value. For example, leaves of C. sinensis plants can be used to produce tea and seeds of C. oleifera plants can be used to produce edible oil, while C. japonica plants are useful as ornamental plants.
With the development of the modern feed industry, a number of antibiotics have been used as feed additive to prevent animal diseases and to promote animal growth. In 1990, while about 2000 tons of antibiotics were used as feed additives in China, about 1350 tons and 1300 tons of antibiotics were used in West Europe and Japan, respectively, in poultry and livestock feed. Recently, sale value of antibiotics reached US $1.019 billions in the USA and utilization of antibiotics is increasing by 3% annually world wide. Long-term utilization of antibiotics, however, can result in drug-resistance of microbes which will create world-wide environment pollution via R-factor translocation, and residual problem in animal products which will be a that to human health. The WHO (World Health Organization) and the FAO (Food and Agriculture Organization, United Nations) are taking great consideration about research on alternatives of antibiotics as feed additives. Currently, research and development on natural material as a feed additive has made a great deal of progress. For example, feed microbes and traditional Chinese medicines have been used extensively. However, feed microbes are prone to becoming inactive during feed processing and can only replace antibiotics partially. Traditional Chinese medicine additives can not be used extensively, due to their sophistication in composition and instability in function. Therefore, there is a necessity to (1) use natural bioactive ingredients as feed additive to replace antibiotics, (2) exclude the residue of antibiotics residue in animal products, (3) improve product quality, and (4) alleviate environmental pollution.
S. Aoyama first separated thea saponin from tea seed cake in 1931. (Journal of Pharmacology, 51(5): 367, 1931). However he did not obtained this pure chemical. In 1952, M. Ishidate and Y. Ueda of Tokyo University obtained the pure crystals of thea saponin. (Ishidate, M. and Ueda, Y., Journal of Pharmacology, 72 (11): 1525, 1952.). From the 1970's, a series of studies on separation, characterization and utilization of thea saponin were conducted in major tea-producing countries. Many extracting methods and products had been developed during this period.
It is now clear that saponin obtained from Camellia L. belongs to triterpenoid compounds. It is a group of complicated compounds composed of aglycone (C.sub.30 H.sub.50 O.sub.6), sugars and organic acids. The chemical structures of saponin obtained from Camellia L. have been disclosed in many references. For example, in I. Yoshioka et al., Chemical Pharmacology Bulletin (Tokyo) 1970, 18. 1610; Yoshioka, et al., Thea sapogenol A., The Major Sapogenol of the Seeds Saponin of Thea"; Sinensis L., Tetrahedron Letters, 1966 (48): 5979-5984, 5973-5978; and I. Yoshioka, et al., Saponin and Sapogenol III Seeds Sapogenols of Thea Sinensis L (3), Thea Sapogenol E and Minor Sapogenols, Chem. Phar. Bull. 1971, 19 (6) 1186-1199.
Development in thea saponin research offers great opportunity for complete utilization of by-products of tea seed and tea leaves. In 1972, G. R. Roberts and his colleague (G. R. Roberts et al., Tea QUARTERLY 43 (3), 1972) from Sri Lanka improved thea saponin extracting technology, industrialized its preparation, and suggested several other methods to use tea seed cake from Camellia plants, (R. L. Wickremastinghe et al., 1972. Tea Quarterly 43 (3)). As estimated by T. Yaziciglu and his colleague, about 600 tons of thea saponin could be extracted from 15,000 tons of tea seed in Turkey. So far, industrialization of thea saponin production has been possible, and Nippon Isome Grease Chemical Co. is already commercializing the production of thea saponin.
Saponin obtained from Camellia L. has extensive utilization in industry. Its utilization in medicine was the earliest research field. However, this field developed slowly though there are many pharmacologists investigating the problem. Pharmacological effects of the saponin include antiosmosis, antiphlogistics, and control of coughing. It was reported that the saponin has special effect on many kinds of oedema (dropsy).
Industry utilization of saponin obtained from Camellia L. is a newly developed field. It could be used to produce kinds of water and oil emulsion, preservatives, foaming agent in the beer industry and detergents in daily industry. It could maintain the color of fabrics as it resists damage to dye on the fabrics. When used in laundering process, it prevents shrinking of woolen products and maintains the luster of fabrics as well. The saponin can also be used in photographic industry.
Saponin obtained from Camellia has extensive usage in agriculture, expecially as insecticide, germicide and binding agent in spray pesticide. Its major benefit is to avoid pesticide residue and protect environment.
However, research on the utilization of saponin obtained from Camellia as feed additive to replace antibiotics has not been documented yet, nor have the effects of said saponin on animal growth and immune function promotion.
After research and development of saponin obtained from Camellia L. for many years, the present inventor has unexpectedly found that saponins extracted from the seed cake of Camellia L. could improve immune function and has the added beneficial effects of being anti-bacterial and anti-viral. It is, in fact, safe for animal consumption under some conditions and can enhance the growth of the animals.
It is one object of the present invention to provide a method of promoting the growth of animals.
It is another object of the present invention to provide a method of improving immune function and anti-bacterial and anti-viral effects.
It is another object of the present invention to provide a use of the bioactive extract of oil plants as feed additive.
It is another object of the present invention to provide a novel health care agent.